This is the big question but if you think things through in advance it is not too difficult. The key points to consider are as follows:-
Be reasonable and realistic
Don’t ask a small company for a large amount of cash, they will most likely say no
Some sponsors will be happy to give you money, but don’t always think of sponsorship support as hard cash. A sponsor that can provide you with free products, equipment or services is just as useful, if not more so, than a company offering money.
How much you ask for from a sponsor will depend upon what you have to offer, ie. what value you can bring in return.
Consider the type of company you are approaching then determine what it is they could offer you that would be of little or no cost to them (ie. A free mobile and contract from a mobile phone company, a courtesy car from a car dealership, free flights from an Airline etc)
Have an idea of what a company is likely to be able to spend. A local butchers, for example, will not have the same budget as the local bank
They may ask for a budget so set out a budget for yourself; make it realistic but don’t underestimate. Include all outgoings relating to your sporting activity and general living expenses, including your travel costs, rent, training equipment, professional services (physio etc) etc.
Showing a planned budget will help you as well. They may cover all of it!
Show value for money - results for less cost
Be prepared to be flexible
Always be mindful of the fact that you have a great deal of value to offer a potential sponsor. Sponsorship is not a one-way relationship so never think of yourself as a charity case! Whilst the sponsor can provide you with cash, products or services, you can also deliver value to their business/brand – if that weren’t the case, sponsorship wouldn’t exist. So don’t undersell yourself. Be confident and talk yourself up, but be careful not to cross the line and appear arrogant. This can be a turn off to sponsors.